The waste waters forming in mining galleries, the so-called pit water, is collected in sludge. Such sludge galleries are provided in the area or underneath the deepest mining floor and serve solely for the collection of the pit water, which is evacuated from there to the surface with the aid of pumps. In a sludge gallery, the heavy particles collect, i.e. the sludge settles at the bottom, so that after such a sludge gallery is pumped empty of the pit water, the resulting sludge is aspirated from the floor and then as a rule transported via conveyor trucks to the surface.
From the Trade Journal of the Ruhrkohle Aktiengesellschaft 2/85 (BAG Niederrhein), an apparatus is known which sweeps together the sludge under water and then aspirates it through pumps. A clearing shield is provided on a movable bridge and swingably supported thereon, with an eccentric worm pump hanging in front of the clearing shield which aspirates the collected sludge, and after further treatment, for instance dewatering through centrifugal action, the sludge is transferred to large conveyor trucks, which carry the material to the surface. In this known system, a first disadvantage is that the permanently is stationarily located in such a sludge gallery, and as a result is not available for other operations, e.g. for another sludge gallery. Another disadvantage is also the considerable deployment of machines, whereby due to the relatively watery material, the intervention of a solid-jacket worm centrifuge is required. Only after the treatment in this centrifuge does it becomes possible to evacuate the material in open 3000 1 trucks.